Search Publications
Regulation of the solar wind electron heat flux from 1 to 5 AU: Ulysses observations
Gary, S. Peter; Scime, Earl E.; Bame, Samuel J. +3 more
In this study we use observations from the three-dimensional electron spectrometer and magnetometer aboard the Ulysses spacecraft to examine the solar wind electron heat flux from 1.2 to 5.4 AU in the ecliptic plane. Throughout Ulysses' transit to 5.4 AU, the electron heat flux decreases more rapidly (~R-3.0) than simple collisionless e…
Ion injection and acceleration at quasi-perpendicular shocks
Giacalone, J.; Jokipii, J. R.; Kota, J.
We present and discuss results of a new model for ion injection and acceleration at quasi-perpendicular collisionless shocks. We use the one-dimensional hybrid simulation (kinetic ions/fluid electrons) and impose an assumption on the ion motion so that diffusion across the magnetic field (normal to the shock front) is possible. These motions are o…
Hubble Space Telescope UV spectral observations of Io passing into eclipse
Schneider, N.; Luhmann, J.; Clarke, J. T. +2 more
Time-resolved spectra of Io have been obtianed with the Faint Object Spectrograph on the Hubble Space Telescope in January 1992 at times centered on the passage of Io into Jupiter's shadow. Two different eclipse observations covered 1100-1600 Å and 2250-3300 Å. In the far-UV range, emission lines of atomic sulfur and oxygen from Io's atmosphere (s…
Effects of spacecraft potential on three-dimensional electron measurements in the solar wind
Scime, Earl E.; Bame, Samuel J.; Phillips, John L.
Using the three-dimensional, low-energy electron spectrometer aboard the Ulysses spacecraft, we have measured the gyrotropicity of electron distributions in the solar wind. In order to make these observations, we have developed a new technique for correcting spacecraft charging effects in three-dimensional, low-energy particle measurements. Compar…
Auroral Lyman α and H2 bands from the giant planets: 1. Excitation by proton precipitation in the Jovian atmosphere
Prange, Renee; Rego, Daniel; Gerard, Jean-Claude
This paper is part of a work aimed at modeling the ratio of the observed Jovian auroral intensity at H Lyman α and in the H2 Lyman and Werner bands and interpreting them as diagnostic of the incident magnetospheric particle species and energy. The work is planned in three steps: (1) modeling of the volume excitation rate, (2) modeling o…
Ulysses near-ecliptic observations of differential flow between protons and alphas in the solar wind
Goldstein, B. E.; Bame, S. J.; Neugebauer, M. +1 more
The evolution of differential streaming between protons and alpha particles in the solar wind was observed with the solar wind plasma experiment on the Ulysses spacecraft over the solar range of 1.15 to 5.40 AU between November 18, 1990, and May 5, 1992. The correlation of the difference in ion speeds, ΔV=||Vα||-||Vp||, with …
An analysis of whistler waves at interplanetary shocks
Forsyth, R.; Balogh, A.; Farrell, W. M. +2 more
We present an analysis of whistler wave magnetic and electric field amplitude ratios from which we compute wave propagation angles and energies of electrons in resonance with the waves. To do this analysis, we compute the theoretical dependence of ratios of wave components on the whistler wave propagation angle Theta for various combinations of or…
The induced magnetosphere of comet Halley: Interplanetary magnetic field during Giotto encounter
Neubauer, F. M.; Israelevich, P. L.; Ershkovich, A. I.
Direction of the interplanetary magnetic field (IMF) which governs the orientation of the Halley's magnetosphere was restored by using Giotto magnetic field data. The Giotto trajectory was a twisted curve in the coordinate system rotating with IMF vector and covered rather uniformly the transverse cross section of the comet. Magnetic field vectors…
There is no ``cometopause'' at Comet Halley
Chaizy, P.; Reme, H.; Korth, A. +3 more
Immediately after the flybys at comet Halley by a fleet of spacecraft in 1986, Gringauz et al. (1986a) reported the detection by the Vega-2 spacecraft of a chemical and sharp plasma boundary, which they named the ``cometopause,'' at a distance of ~1.6×105 km from the nucleus. Gringauz and Verigin (1991) presented the ``cometopause'' as …
Asymmetries in the Io plasma torus
Kaiser, M. L.; Desch, M. D.; Farrell, W. M.
Using Ulysses radio wave data taken during the 1992 Jupiter encounter, we conclude that there are significant large and small spatial scale azimuthal asymmetries at high latitudes in the Io plasma torus. During a period of time near perijove when the spacecraft motion was predominantly in the azimuthal direction and was relatively fixed in both la…